\begin{tikzpicture}
    \tkzDefPoints{0/0/B,  4/0/C,  2/2.5/A}
    \tkzDefPointOnLine[pos=0.3](B,C)  \tkzGetPoint{D}
    \tkzDefPointOnLine[pos=0.3](C,B)  \tkzGetPoint{E}
    \tkzDrawPolygon(A,B,C)
    \tkzDrawSegments(A,D  A,E)
    \tkzLabelPoints[above](A)
    \tkzLabelPoints[below](B,C,D,E)
\end{tikzpicture}

